Water has unique properties that make it essential for life. It is polar and can form hydrogen bonds, giving it high surface tension and allowing it to be an excellent solvent. Water also has a high heat capacity and heat of vaporization, enabling it to buffer temperatures. Its density peaks at 4°C, and it is less dense as a solid due to its crystalline structure - properties important for organisms. Overall, water's polarity and ability to form bonds give it characteristics that sustain all known lifeforms.

1. MAHANTHESHKUMAR.G.T
MSc,Biotchnology
Dept,of biotech.
Sahyadri science college shivamogga.

2. Welcome you all to the Department of
Biotechnology
2

3. Biotechnology
During 1970s, biotechnology emerged as a new discipline, as a
result of marriage of biological science with technology.
The term biotechnology was coined in 1917 by a Hungarian
Engineer Karl Ereky.
Biotechnology is not a pure science, but an integrated effort of
these two, the root of which lies in biological science.

4. DEFINITIONS
Biotechnology is the application of scientific and
engineering principles to the processing of materials by
biological agents to provide goods and service. [The
Organization for Economic Cooperation and
Development (OECD), 1981].
The integrated use of biochemistry, microbiology and
engineering sciences in order to achieve technological
application of the capabilities of microorganisms,
cultured tissue, cells, and parts their
of [The European Federation of Biotechnology
(EFB)]

6. Biotechnology is an
interdisciplinary subject where we
need the an understanding of
various basic and applied
concepts of biology

7. Chemistry of Biomolecules and Cellular
Metabolism
Genetics and Molecular Biology
Microbiology
Biochemical Techniques, Biostatistics and
Bioinformatics

8. •Carl Neuberg (1903)
•Biochemistry is the chemistry of
the living world.
•Biochemistry is the science which
is concerned with the chemical
reactions associated with biological
processes

9. 1. The structure and properties of substances constituting the
frame work of cells and tissues
2. The structure and properties of substances which enter the cell
as useful working materials or sources of energy or leaving the
cell as waste products
3. The metabolism or the chemical changes with in the cell
4. The molecular basis for the performance of various forms of
work by the cell
5. The energy changes occurring in the processes 2 and 3.

10. • 2/3 of the globe is covered in
water.
•2/3 of all cells contain water.
•Water is the only substance in
world to be found naturally in all 3
states. (Solid: Ice, Liquid: Water,
Gas: Water Vapor.
•Water freezes at 00
C and boils at
1000
C.

11. A Water molecule consists of two
Hydrogen atoms covalently
bonded to an Oxygen atom.
Because oxygen is more
electronegative than hydrogen, it
has a greater pull on the shared
electrons.
This that the oxygen atom is
slightly negative (δ-) (because of
the closer electrons), and
hydrogen is slightly positive (δ+).
Water is therefore called a Polar
Molecule.

12. 12
slightly positive
charge
slightly negative charge
hydrogen bond between
(+) and (-) areas of
different water molecules
Water molecules form Hydrogen bonds

13. HYDROGEN BONDS
Hold water molecules
together
Each water molecule
can form a maximum
of 4 hydrogen bonds
The hydrogen bonds
joining water
molecules are weak,
about 1/20th
as strong as
covalent bonds.
They form, break, and
reform with great
frequency
Extraordinary Properties
that are a result of
hydrogen bonds.
Cohesive behavior
Resists changes in
temperature
High heat of vaporization
Expands when it freezes
Versatile solvent

14. Water Can Ionize to Form H+
and OH-
The ionization of water

15. The attractive forces between water molecules and the
slight tendency of water to ionize are of crucial
importance to the structure and function of biomolecules.
Water has a number of unique properties that are
essential to life and that determine its environmental
chemical behavior. Many of these properties are due to
water is polar molecular structure and its ability to form
hydrogen bonds.

16. Water in organisms
Organisms usually contain
60% to 90% water.
Lowest- Plant Seed (20%)
Highest- Jellyfish (99%)
Water helps all organisms
with metabolism, and
specifically helps plants
with photosynthesis and
support.
99%
Water
20%
Water

17. Water as a solvent
The water molecule is said
to be polar, because
electrons are not equally
shared.
Because the water
molecule is polar, it can
ionize substances easily,
making it a good solvent.
Water is know as ‘The
Universal Solvent’.

18. Water as a way of transport
Many different substances,
such as blood and sap, are
transported by water.
Sap and blood contain
high amounts of water
making them good
solvents.
Being good solvents allows
them to dissolve the
substances they are
transporting.
Tree Sap
Human
Blood Cells

19. Water As A Reactant
Water, being a good solvent,
allows many reactions to occur.
Water is used in photosynthesis
to make NADPH2, and
ultimately sugar.
These reactions release oxygen
gas, which is vital to human life.
Without water in
photosynthesis, organisms
would not be able to obtain
energy, and life as we know it
would be impossible.

20. Water As A Way Of Support
When water enters the cell by
osmosis, the water fills up the cell
so much that the cell prevents
other water intake.
This makes the cell turgid, or stiff.
The cell must be turgid to support
the plant’s leaves.
Also, organisms that live in the
water have weaker skeletons than
organisms that live on land
because of the water’s buoyancy
effect.

21. Water As A Lubricant
When bones meet at a joint, they
need a fluid between the bones to
prevent scraping against each
other.
That fluid is called a synovial fluid,
which is made mainly of water.
Many internal organs have fluid
around them to keep them
protected. Examples:
Brain: Cerebro-spinal fluid
Lungs: Pleural Fluid
Eyes: Mix of fluids.
Synovial
Fluid

22. Water In Sexual Reproduction
During fertilization, the male sex
cell, the sperm, must get to the
female sex cell, the ovum in order
to make the zygote, which makes
a new individual.
In organisms adapted for internal
fertilization, the sperm is
transported in semen which
contains mostly water.
In organisms using external
sperm can be transported in the
water habitat.
Sperm Cells

23. Water As A Habitat
Here are some good reasons why
water is a good habitat:
1. Water can provide a good
protective layer for organisms in it.
2. Water provides buoyancy and
support for organisms in the
water.
3. Dissolved oxygen can be plentiful
in water, for use in respiration.
4. Fertilization is easier in water.
5. Water helps maintain a constant
temperature.
6.Water keeps out UV rays from the
sun.

24. THE PROPERTIES OF WATER
- Excellent solvent
- Highest dielectric constant of any common liquid.
- Higher surface tension than any other liquid.
- Transparent to visible and longer-wavelength fraction of
ultraviolet light.
- Maximum density as liquid at 4 o
C.
- Higher heat of evaporation than any other material.
- Higher latent heat of fusion than any other liquid except
ammonia
- Higher heat capacity than any other liquid except
ammonia

25. “Universal” Solvent
A liquid that is a completely homogeneous mixture of two
or more substances is called a solution.
A sugar cube in a glass of water will eventually dissolve
to form a uniform mixture of sugar and water.
The dissolving agent is the solvent and the substance that
is dissolved is the solute.
In our example, water is the solvent and sugar the
solute.
In an aqueous solution, water is the solvent.

26. Water is an effective
solvent as it can form
hydrogen bonds.
Water clings to polar
molecules causing them
to be soluble in water.
 Hydrophilic -
attracted to water
 Hydrophobic -
repelled by water
 Water causes
hydrophobic
molecules to
aggregate or assume
specific shapes.

27. The Solvent Properties of Water Derive
from Its Polar Nature
Water has a high dielectric
constant.
Dielectric constant is a
measure of the ability of a
solvent to solvate ions.
Water forms H-bonds with
polar solutes.
Hydrophobic interactions -
a "secret of life“.

28. cohesion = water attracted to other water
molecules because of polar properties
adhesion = water attracted to other materials
surface tension = water is pulled together
creating the smallest surface area possible
Cohesion, Adhesion and Surface Tension

29. Surface tension, a measure of the force necessary to
stretch or break the surface of a liquid, is related to
cohesion.
Water has a greater surface tension than most other liquids
because hydrogen bonds among surface water molecules
resist stretching or breaking the surface.
Water behaves as if
covered by an invisible
film.
Some animals can stand,
walk, or run on water
without breaking the
surface.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 3.3

30. Adhesion refers to
attraction to other
substances.
Water is adhesive to
any substance with
which it can form
hydrogen bonds.
Adhesion

31. Capillary action
water evaporates from leaves =
transpiration
adhesion,
cohesion and
capillary action
water taken up by roots
Because water has
both adhesive and
cohesive properties,
capillary action is
present.

32. In order to raise the temperature of water, the average
molecular speed has to increase.
It takes much more energy to raise the temperature of water
compared to other solvents because hydrogen bonds hold
the water molecules together!
Water has a high heat capacity.
“The specific heat is the amount of heat per unit mass
required to raise the temperature by one degree
Celsius.”
High Heat Capacity/High specific heat

33. High Heat of Vaporization
High heat of vaporization
Amount of energy required to change 1g of liquid water
into a gas (586 calories). large number of hydrogen
bonds broken when heat energy is applied

34. Water For Constant Temperature
 Water has a very high specific heat.
(4200J/kg0C)
 That means much energy is
required to change the temperature
of water by a single degree.
 That provides a perfect habitat for
marine mammals, because of the
non-changing temperature.
 Another way water helps mammals
maintain their body temperature is
by sweating.
 Mammals sweat when their body
temperature is too high.
 Sweat is made of mostly water.
 When the water evaporates from
the organism it creates a cooling
effect, therefore lowering the
organisms body temperature.

35. As a liquid evaporates, the surface of the
liquid that remains behind cools -
Evaporative cooling.
Evaporative cooling moderates
temperature in lakes and ponds and
prevents terrestrial organisms from
overheating.
Evaporation of water from the leaves of
plants or the skin of animals removes
excess heat.

36. Density
Water is less dense as a solid!
This is because the hydrogen bonds are stable in ice –
each molecule of water is bound to four of its
neighbors.
Solid – water molecules
are bonded together –
space between fixed
Liquid – water molecules
are constantly bonding
and rebonding – space is
always changing
same mass but
a larger volume Density = mass/volume

37. When water reaches 0o
C, water becomes locked into a
crystalline lattice with each molecule bonded to the
maximum of four partners.
As ice starts to melt, some of the hydrogen bonds break
and some water molecules can slip closer together than
they can while in the ice state.
Ice is about 10% less dense than water at 4o
C.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 3.5

38. Density of Water
Most dense at 4o
C
Contracts until 4o
C
Expands from 4o
C
to 0o
C
The density of water:
1. Prevents water from freezing from the bottom up.
2. Ice forms on the surface first—the freezing of the
water releases heat to the water below creating
insulation. (organisms can still live in the water
underneath the ice during winter)
3. Makes transition between season less abrupt.

39. Water is Transparent
The fact that water is clear allows light to pass
through it
Aquatic plants can receive sunlight
Light can pass through the eyeball to receptor cells
in the back

40. Properties of Water
So, can you name all of the properties of water?
Adhesion
Cohesion
Capillary action
High surface tension
Holds heat to regulate temperature (High heat capacity)
Less dense as a solid than a liquid